Envelope tracking amplifier apparatus

• US 10,630,375 B1
• Filed: 02/12/2019
• Issued: 04/21/2020
• Est. Priority Date: 10/19/2018
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Inventors: Khlat, Nadim
• Primary Examiner(s): Nguyen, Hai V
• Application Number:
  US16/273,288
• Publication Number:
  US 20200127730A1
• Time in Patent Office: 434 Days
• Field of Search: 455522, 455 69
• CPC Class Codes: H03F 1/0211 with control of the supply voltage or current
• CPC Class Codes: H03F 1/0222 by using a signal derived from the input signal
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• CPC Class Codes: H03F 2200/111 the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not
• CPC Class Codes: H03F 2200/451 the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2203/7209 the gated amplifier being switched from a first band to a second band
• CPC Class Codes: H03F 3/19 with semiconductor devices only
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/68 Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602
• CPC Class Codes: H03F 3/72 Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 2001/0408 with power amplifiers
• CPC Class Codes: H04B 7/15535 Control of relay amplifier gain amplifier gain control in general H03G3/00; gain control reducing self - or loop interference H04B7/15578

Abstract

An envelope tracking (ET) amplifier apparatus is provided. The ET amplifier apparatus includes a number of amplifier circuits that can be activated concurrently or selectively for amplifying a number of radio frequency (RF) signals. Notably, some amplifier circuits may amplify RF signals corresponding to a higher modulation bandwidth (e.g., >80 MHz), while other amplifier circuits may amplify RF signals corresponding to a lower modulation bandwidth (e.g., <40 MHz). In examples discussed herein, the ET amplifier apparatus can be flexibly configured to the amplifier circuits, either concurrently or selectively, to amplify the RF signals corresponding to a wide range of modulation bandwidths, without compromising linearity and efficiency of the amplifier circuits. Moreover, the ET amplifier apparatus may be configured to share a common circuit(s) among a number of circuits, thus helping to reduce footprint of the ET amplifier apparatus.

Claims

1. An envelope tracking (ET) amplifier apparatus comprising:

a distributed ET amplifier circuit comprising;

a first amplifier circuit configured to amplify a radio frequency (RF) signal based on a first ET voltage;

a first ET circuit configured to generate the first ET voltage;

a second amplifier circuit configured to amplify the RF signal based on a second ET voltage; and

a second ET circuit configured to generate the second ET voltage;

a first auxiliary amplifier circuit configured to amplify a first RF signal based on a first auxiliary voltage;

a second auxiliary amplifier circuit configured to amplify a second RF signal based on a second auxiliary voltage; and

an ET integrated circuit (ETIC) configured to;

cause at least one ET circuit among the first ET circuit and the second ET circuit to provide at least one ET voltage among the first ET voltage and the second ET voltage to at least one amplifier circuit among the first amplifier circuit and the second amplifier circuit in response to determining that the at least one amplifier circuit is activated; and

provide at least one auxiliary voltage among the first auxiliary voltage and the second auxiliary voltage to at least one auxiliary amplifier circuit among the first auxiliary amplifier circuit and the second auxiliary amplifier circuit in response to determining that the at least one auxiliary amplifier circuit is activated.

2. The ET amplifier apparatus of claim 1 wherein the distributed ET amplifier circuit further comprises a first target voltage circuit and a second target voltage circuit configured to generate a first ET target voltage and a second ET target voltage for the first ET circuit and the second ET circuit, respectively.

3. The ET amplifier apparatus of claim 1 wherein the ETIC comprises:

a supply voltage circuit configured to generate a plurality of supply voltages based on a battery voltage;

a first auxiliary interface circuit configured to;

receive a constant auxiliary voltage, a first ET auxiliary voltage, and a second ET auxiliary voltage;

determine the first auxiliary voltage among the constant auxiliary voltage, the first ET auxiliary voltage, and the second ET auxiliary voltage; and

provide the first auxiliary voltage to the first auxiliary amplifier circuit;

a second auxiliary interface circuit configured to;

receive the constant auxiliary voltage, the first ET auxiliary voltage, and the second ET auxiliary voltage;

determine the second auxiliary voltage among the constant auxiliary voltage, the first ET auxiliary voltage, and the second ET auxiliary voltage; and

provide the second auxiliary voltage to the second auxiliary amplifier circuit; and

a voltage selection circuit coupled to the supply voltage circuit and configured to;

select the constant auxiliary voltage among the plurality of supply voltages; and

provide the constant auxiliary voltage to the first auxiliary interface circuit and the second auxiliary interface circuit.

4. The ET amplifier apparatus of claim 3 wherein the voltage selection circuit comprises:

a multiplexer configured to receive the plurality of supply voltages from the supply voltage circuit and selectively output the constant auxiliary voltage among the plurality of supply voltages; and

a low-drop out (LDO) regulator configured to receive and output the constant auxiliary voltage.

5. The ET amplifier apparatus of claim 3 wherein the ETIC further comprises:

a first multi-level charge pump (MCP) coupled to the supply voltage circuit and configured to selectively output a first direct current voltage among the plurality of supply voltages and the battery voltage;

a second MCP coupled to the supply voltage circuit and configured to selectively output a second direct current voltage among the plurality of supply voltages and the battery voltage; and

a target voltage circuit configured to generate a first ET target voltage and a second ET target voltage for the first ET circuit and the second ET circuit, respectively.

6. The ET amplifier apparatus of claim 5 wherein the target voltage circuit comprises:

a first target voltage circuit configured to generate the first ET target voltage; and

a second target voltage circuit configured to generate the second ET target voltage.

7. The ET amplifier apparatus of claim 5 wherein the first MCP comprises switching circuitry coupled to the supply voltage circuit and configured to selectively output the first direct current voltage among the plurality of supply voltages and the battery voltage.

8. The ET amplifier apparatus of claim 5 wherein the second MCP comprises switching circuitry coupled to the supply voltage circuit and configured to selectively output the second direct current voltage among the plurality of supply voltages and the battery voltage.

9. The ET amplifier apparatus of claim 5 wherein the ETIC further comprises:

a first inductor coupled between the first MCP and the first amplifier circuit and configured to;

induce a first low-frequency current based on the first direct current voltage; and

provide the first low-frequency current to the first amplifier circuit; and

a second inductor coupled between the second MCP and the second amplifier circuit and configured to;

induce a second low-frequency current based on the second direct current voltage; and

provide the second low-frequency current to the second amplifier circuit.

10. The ET amplifier apparatus of claim 5 wherein:

the first ET circuit comprises a first distributed voltage amplifier configured to;

receive the plurality of supply voltages from the supply voltage circuit;

receive the first ET target voltage from the target voltage circuit; and

generate a first initial ET voltage based on the plurality of supply voltages and the first ET target voltage; and

the second ET circuit comprises a second distributed voltage amplifier configured to;

receive the plurality of supply voltages from the supply voltage circuit;

receive the second ET target voltage from the target voltage circuit; and

generate a second initial ET voltage based on the plurality of supply voltages and the second ET target voltage.

11. The ET amplifier apparatus of claim 10 wherein:

the first ET circuit further comprises a first offset capacitor coupled between the first distributed voltage amplifier and the first amplifier circuit, the first offset capacitor configured to raise the first initial ET voltage by a first offset voltage to generate the first ET voltage; and

the second ET circuit further comprises a second offset capacitor coupled between the second distributed voltage amplifier and the second amplifier circuit, the second offset capacitor configured to raise the second initial ET voltage by a second offset voltage to generate the second ET voltage.

12. The ET amplifier apparatus of claim 3 wherein:

each of the first amplifier circuit and the second amplifier circuit comprises a first-stage amplifier, a second-stage amplifier, and a third-stage amplifier; and

the distributed ET amplifier circuit further comprises a distributed voltage selection circuit configured to;

receive the plurality of supply voltages from the supply voltage circuit; and

determine and provide a selected supply voltage among the plurality of supply voltages to the first-stage amplifier in the first amplifier circuit and the second amplifier circuit.

13. The ET amplifier apparatus of claim 3 wherein the ETIC further comprises a controller configured to:

control the supply voltage circuit configured to generate the plurality of supply voltages based on the battery voltage;

control the first auxiliary interface circuit configured to selectively output the first auxiliary voltage among the constant auxiliary voltage, the first ET voltage, and the second ET voltage;

control the second auxiliary interface circuit to selectively output the second auxiliary voltage among the constant auxiliary voltage, the first ET voltage, and the second ET voltage; and

control the voltage selection circuit coupled to selectively provide the constant auxiliary voltage to the first auxiliary interface circuit and the second auxiliary interface circuit.

14. The ET amplifier apparatus of claim 13 wherein the distributed ET amplifier circuit further comprises a distributed controller communicatively coupled to the controller and configured to:

determine the at least one amplifier circuit that is activated; and

control the at least one ET circuit to provide the at least one ET voltage to the at least one amplifier circuit in response to determining that the at least one amplifier circuit is activated.

15. The ET amplifier apparatus of claim 14 wherein the distributed controller is communicatively coupled to the controller via one or more RF front-end (RFFE) interfaces.

16. The ET amplifier apparatus of claim 1 wherein the ETIC is further configured to:

determine that the first amplifier circuit, the second amplifier circuit, the first auxiliary amplifier circuit, and the second auxiliary amplifier circuit are concurrently activated;

cause the first ET circuit and the second ET circuit to provide the first ET voltage and the second ET voltage to the first amplifier circuit and the second amplifier circuit, respectively; and

provide the first auxiliary voltage and the second auxiliary voltage to the first auxiliary amplifier circuit and the second auxiliary amplifier circuit, respectively.

17. The ET amplifier apparatus of claim 1 wherein the ETIC is further configured to:

determine that the second amplifier circuit, the first auxiliary amplifier circuit, and the second auxiliary amplifier circuit are concurrently activated while the first amplifier circuit is deactivated;

cause the second ET circuit to provide the second ET voltage to the second amplifier circuit; and

cause the first ET circuit to provide the first ET voltage to the first auxiliary amplifier circuit and the second auxiliary amplifier circuit.

18. The ET amplifier apparatus of claim 1 wherein the ETIC comprises:

a first main voltage amplifier configured to generate a first ET auxiliary voltage based on a first main ET target voltage; and

a second main voltage amplifier configured to generate a second ET auxiliary voltage based on a second main ET target voltage.

19. The ET amplifier apparatus of claim 18 wherein the ETIC is further configured to:

determine that the first amplifier circuit, the second amplifier circuit, the first auxiliary amplifier circuit, and the second auxiliary amplifier circuit are concurrently activated;

cause the first ET circuit and the second ET circuit to provide the first ET voltage and the second ET voltage to the first amplifier circuit and the second amplifier circuit, respectively; and

activate the first main voltage amplifier and the second main voltage amplifier to provide the first ET auxiliary voltage and the second ET auxiliary voltage to the first auxiliary amplifier circuit and the second auxiliary amplifier circuit, respectively.

20. The ET amplifier apparatus of claim 18 wherein the ETIC further comprises a first target voltage circuit and a second target voltage circuit configured to generate the first main ET target voltage and the second main ET target voltage, respectively.